A current sense amplifier system may sense a current using a small sense resistor to generate a small sense voltage that is proportional to the sensed current. An amplifier of the current sense amplifier system is then used to amplify the small sense voltage. One such system is shown in FIG. 1. FIG. 1 is an example schematic block diagram illustrating a conventional current sense amplifier system according to the prior art. As illustrated in FIG. 1, a current being sensed by current sense amplifier system 100 corresponds to the current flowing through speaker 102. Current sense amplifier system 100 may also include an analog-to-digital converter (ADC) 104 to convert the analog sensed voltage signal to a digital sensed voltage signal suitable for digital post-processing.
Numerous drawbacks are associated with conventional current sense amplifier system of FIG. 1, and others. For example, a common mode voltage feed through may occur due to a mismatch between resistors 108A and 108B. The problem is exacerbated by the fact that the sense voltage is small compared to the common mode voltage, such that even a slight mismatch between resistors 108A and 108B can result in a common mode feed through voltage that is a significant percentage of the sense voltage. Another common problem is that the common mode input range of the amplifier may be narrow, limiting the range of operability of the current sense amplifier system.
Shortcomings mentioned here are only representative and are included simply to highlight that a need exists for improved electrical components, particularly for current sense amplifiers employed in consumer-level devices, such as mobile phones. Embodiments described herein address certain shortcomings but not necessarily each and every one described here or known in the art.